A simple swab of the cheek may hold the answer to Mary Ann Mahometa’s diet problem. She told CBS 2’s Kristine Johnson recently that she’s been struggling with her weight for years.

“The weight just kind of comes on a little at a time; half pound, a pound, two pounds a year and you don’t really notice it until you start feeling a little sluggish, the clothes don’t fit quite the way they used to,” Mahometa said.

“It’s an incredible tool. It really is because then you know how you have to change your diet based on your own personal results,” nutritionist Jennifer Burns said.

The test is easy. Collect a DNA sample from inside your cheek and mail it away for analysis. The results will arrive in about two weeks.

To get the most out of it, Mahometa said she went over her results with a nutritionist.

“It talks about food and makes it a little more realistic. You understand about carbs; you understand fats; you understand being a better balance,” Burns said.

Mahometa’s test indicated that a diet low in fats, with high-intensity exercise was best suited for her. In four months, she lost 17 pounds.

Linda Marcel also took this DNA test. As with Mahometa, Marcel said she discovered she, too, was best suited for a low-fat diet with high-intensity exercise. Over two years she said she lost 50 pounds and managed to keep it off.

“It gives me the power and the control that I always wanted,” Marcel said.

“When you look at the genetic tests they are basically looking at what you’re metabolic rate is. They look to see if you are predisposed to other illnesses. They’re going to tailor your diet based on those risk factors,” Dr. Lisa Ghanju said.

Carolyn Katzin is the founder of another DNA Diet. She said she uses patients’ existing medical tests as well as a questionnaire to determine a diet best suited for their genetic makeup.

“Some people are very frustrated. Why they find weight loss so difficult is because they have a very slow metabolism and you really can’t tell by looking at yourself if that’s the case. You need to do some imaging and testing,” Katzin said.

“Carolyn has gotten to the bottom of things where I need more protein; I need more omegas in my diet. The way she shaped it towards me makes it much easier for me to include in my lifestyle,” patient Jocelyn Story said.

DNA Diet test kits cost about $170.

“At this point it’s a bit of a novelty and if people are losing weight with it that’s great and I would say keep doing it if that’s working for you,” Dr. Ghanju said.